Re: alarm clock. I got in big trouble with my better half cuz I told her she didn't need to pack her alarm clock. I was certain they had one in the room. NOT! None for sale in the ship's store either. First port stop we had to buy one. She, like you, wakes up during the night and always wants to know what time it is.

Re: Formal attire. Our first two cruises, I rented tuxes from Princess. It was great and I felt like James Bond on the formal nights. The more we cruised, the easier it was to just bring a dark suit (and saved money). Now it is a suit or dark sport coat and nice slacks. I have never felt out of place at dinner.

Have a great time. You will have a blast traveling with a large group of friends.

Grand Princess has shelves and drawers and closet space for clothes. The suitcases do fit under the bed.
My partner wears a suit for formal nights and I usually wear a long dress, not a fancy gown. There are more people attired that way than full formal dress.
The wake up call works great, but I always bring a small travel clock anyway.